Conventional pipes, including filtered pipes, and those equipped with metal fittings which form condensation and taint flavor, function today the same way they have for centuries. A single channel, closed at the heel end, connects the bowl, shank, stem and bit. Liquids generated while smoking run-down the single channel and build-up in the heel of the bowl. Filters and other fittings in the smoke channel slow or modify the moisture build-up, but eventually the liquids will enter the bowl and will be absorbed by the tobacco. This condition generally continues until about one-fourth of the tobacco in the lower bowl become saturated with collected liquids.
When the burning tobacco in the upper part of the bowl reaches a saturated tobacco in the lower part of the bowl, combustion is gradually reduced as the degree of wetness is increased. The condition essentially becomes akin to that of trying to burn wet leaves. From the moisture level of the tobacco downwards, the flavor supporting carbon cake build-up on the inner walls of the pipe begins to disintegrate and disappear. Moreover, the heat of descending combustion above this level progressively increases the temperature of the confining liquids, causing excessive heat and accelerating the absorption of contaminants.
These circumstances sustain the development of foul odors and bad taste. In addition, the smoke must pass through this collection of hot, acrid condensate producing a biting sensation on the smoker's tongue.
In my U.S. Pat. Nos. 3,028,867 and 3,422,821, dry bowl pipes are disclosed wherein the outer bowl, shank and stem are moulded of a plastic material and wherein and absorbant cartridge is utilized to absorb the liquid combustion products.
In the magazine "Plastics Design Form", published November/December 1977, a third version of an improved dry bowl pipe is disclosed. This version includes a dual fluid path system with an upper smoke path and a lower moisture path.
Pipes formed in accordance with my aforesaid patents, the parent patents to this application, and the disclosure in plastics design forms function extremely well to provide a smooth, cool smoke without the foul taste attendant to the operation of conventional smoker's pipe. However, the appearance of those pipes is unconventional and does not permit twisting of the stem bit, which is turn could cause damage to the models built in accordance with my prior patents.